1. Field of the Invention
The present invention relates to a system for monitoring personal possessions. More specifically, the present invention is a loss prevention system wherein a monitor continuously and automatically surveils electronically tagged personal possessions and sounds an alarm when one or more tagged possessions is removed from proximity to the monitor.
2. Description of the Related Art
The loss of personal possessions is a problem that has spawned numerous and diverse solutions. Small articles, such as a cell phone or pager, television remote controller, briefcase, umbrella, and other articles too numerous to count may be easily lost if carelessly misplaced or accidentally left behind.
One solution to the problem is illustrated by the many “finder” systems that have been devised, wherein an alarm tag is fastened to an article and sounds when commanded by a signal, such as a radio signal, from an alarm control station. When the article is lost, a signal is broadcast from a base station to activate the alarm tag and sound the alarm. The article may then be found by following the sound of the alarm tag.
U.S. Pat. No. 6,297,737, issued on Oct. 21, 2001 to D. Irvin, discloses an object locating system. The system includes a locating unit that comprises a wireless communication interface for transmitting signals to one or more locating tags. When a tagged item is misplaced, a signal is transmitted from the locating unit. When the tag receives the signal, an alarm is sounded. Additionally, the tag sends a response that is received by the locating unit to give an indication that the tagged item is nearby, even if the audio alarm cannot be heard. The system is bi-directional so that a tagged item can be used to find the locating unit itself in the event that the locating unit is misplaced.
U.S. Patent Publication No. 2003/0034887, published on Feb. 20, 2003, discloses an article locator system that employs a tracking transceiver and a handheld locator device. The tracking transceiver is attached to the article to be tracked and sends a response when interrogated by the handheld locator device. The handheld locator device determines the distance and/or direction to the tracking transceiver.
U.S. Patent Publication No. 2002/0126010, published on Sep. 12, 2002, discloses an object locator system employing radio frequency (RF) signaling.
While article finder systems can be a great help in finding lost articles, or even in keeping track of pets and children, the above described article finder systems are typically used in reaction to a loss and not in a manner to prevent the loss. Typical of the article finder systems is the need to manually initiate an action to find the lost article. Additionally, the article finder tags require a power source such as a battery to continuously power a receiver and to power an alarm or transmitter. The article finder tags cease to function when their battery dies, rendering them useless.
Instead of locating an article after it is lost, it is preferable in many circumstances to prevent the loss of the article. Thus, a loss prevention system that signals when an article is removed from a given area, or that signals when an article is left behind, is desirable to help in preventing the article from becoming lost.
European Patent Application 1,288,878, published on Mar. 5, 2003, discloses a security apparatus comprising a base station that interacts with an RFID security tag. The base station comprises an RF transmitter, receiver, and antenna, along with a control unit. The control unit sends a monitoring signal that is received by the RFID tag. The RFID tag is inductively powered by the monitoring signal and responds with an identity signal. Because of the limited range of the monitoring signal and the identity signal, removal of the RFID security tag from proximity to the base station causes the identity signal not to be received by the base station. Thus, when the base station sends a monitoring signal but no identity signal is received in response, an alarm is sounded. In this manner, the security apparatus functions to sound an alarm when a tagged item is removed from proximity to the base station.
U.S. Pat. No. 6,577,238, issued on Jun. 10, 2003 to H. Whitesmith et al., discloses a system for monitoring the position of one or more RFID tags. The system has a detector that incorporates circuitry for detecting changes in the range of an RFID tag from the detector and for triggering an alarm if the range exceeds a predetermined threshold or if the RFID tag cannot be detected by the detector. Range may be determined by measuring the time of a returned radio signal from a tag, by measuring the strength of a returned radio signal from a tag, or by detecting changes in a periodic interval at which a signal is transmitted by a tag.
U.S. Patent Publication No. 2002/0080036, published on Jun. 27, 2002, discloses a system for tracking possessions. The system includes a plurality of child units, each having a transceiver for receiving a control signal and sending a locator signal. The system also includes a parent unit that has a transceiver for communicating with the child units and a processor for monitoring the child units. The system incorporates a GPS receiver in both the parent and child units so that the parent unit can determine the position of, and relative direction and distance to, a child unit.
U.S. Patent Publication No. 2002/0145520, published on Oct. 10, 2002, discloses an object tracking system for tracking the removal of objects from a location and the replacement of the objects at the location. The system includes an RFID tag attached to each of the objects to be tracked. A storage unit has a plurality of receptacles configured to receive objects replaced at the location. Each receptacle has an associated antenna for activating the RFID tag of an object placed in the receptacle.
U.S. Pat. No. 5,289,163, issued on Feb. 22, 1994 to C. Perez et al., discloses a child position monitoring and locating device that monitors the position of a child by detecting the signal strength of a radio frequency carrier from a transmitter attached to the child. If the radio signal is too weak, an alarm notifies the adult that the child is too far away.
U.S. Pat. No. 5,748,087, issued on May 5, 1998 to T. Ingargiola et al., discloses a remote personal security alarm system.
U.S. Patent Publication No. 2003/0063003, published on Apr. 3, 2003, discloses a proximity monitoring communication system wherein an alarm is triggered in a master communication device in a local area network when a slave device in the local area network has strayed from the proximity of the local area network.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a loss prevention system solving the aforementioned problems is desired.